Electric cable and method of manufacturing it



May 26, 1936. R F LAYTQ-N v 2,041,842

ELECTRIC CABLE AND METHOD oF MANUFACTURING `IT Filed June 23, 1932 INVNTOR F. LAVTON A T TORNE Y Patented May 26, 1936 UNITED STATES PATENT OFFICE y ELECTRIC CABLE AND METHOD 0F MANUFACTURING IT s claims. (c1. 17a-zes) The invention relates to an electric cable and method of manufacturing it and more particularly to the type of cables employed in transmit ting intelligence electrically.

Objects of the invention are to provide an improved electric cable and a method of forming the cable.

In the prior art it has been the practice in some instances in connection with the manufacture of v cables for transmitting intelligence electrically to form the cable by stranding pairs of paper insulated conductors together, binding the conductor pairs in a group and finally extruding a sheath of lead or lead alloy over the insulated conductors.

If in place of the lead sheath a. thin metal sheath of copper, brass, zinc,I or; similar metal is applied as a tape directly over a group of assembled conductors having its abutting edges secured in a manner to provide a water-proof cable joint, the tape may have a tendency to rip and crack if the assembled cable is flexed beyond certain limits.

According to one embodiment of the invention herein illustrated and described, a flexible cable for transmitting intelligence electrically is constructed by forming pairs of paper insulated conductors, binding the pairs of conductors into a group, covering the group with a layer of paper applied spirally, applying a layer or layers of metal tape spirally around the conductor core, applying a continuous thin metal tape or skelp over the spirally wound tape, soldering or otherwise joining the edges of the continuous metal tape or skelp together to form a water-tight cable, and applying a suitable protective coating over the continuous tape such as rubber or a wrapping of textile material impregnated with a preserving material.

Other objects and advantages of the invention will appear fromv the following description when considered inl connection with the accompanying drawing in which Fig. 1 is a plan view partially in section of one embodiment of the invention;

Fig. 2 is a plan view partially in'section of another embodiment of the invention;

Fig. 3 is a plan view, partially in section, of still another embodiment of the invention;

Fig. 4 is a vertical sectional view along the line 4-4 of Fig. 1;

Fig. 6 is a vertical sectional view along the line 6 6 of Fig. 3.

Referring to Figs. 1 and 4 of the drawing. a plurality of conductors I0, preferably ofcopper and having low resistance, insulated with paper, textile or other suitable material, are stranded together loosely in layers to form a group or bundle I2. The group or bundle I2 may be formed in any suitable manner, but preferably by the usual and well known form oi' strander which has associated therewith a tape serving head by which a paper Wrapping I3 may be applied spirally to retain the group comprising the conductors Within a predetermined diameter. Surrounding the paper Wrapping I3 is a flexible sheath I5 which is formed by applying a comparatively thin metallic tape or ribbon helically or spirally around the cable so that the edges of adjacent turns slightly overlap each other. The flexible sheath I5 may be composed of a lead alloy, brass, copper, zinc or other suitable material. Surrounding the flexible metal sheath I5 is another flexible metallic sheath 20 formed into the shape of a tube from brass, copper, zinc or other suitable metallic tape'or skelp and having its edges 2I overlapped and joined. The edges 2l may be joined by soldering, brazing, welding, or by other suitable methods. Ifdesired, the lap shown may be omitted and edges 2I of the sheath 20.may be formed to abut each other and secured together by any suitable means Well known in the l art, such as soldering, brazing or welding, to form a water-proof joint.

Over the metal sheath 20 a suitable protective coating 25 is preferably applied. The protective coating 25 may be composed of materials such as tough rubber, gutta percha, gutta percha substitute or other suitable material applied by forcing the cable through an extruding machine of any suitable type well known in the art which applies the covering in one or more layers around the entire length of the cable, or the protective coating may take the form of a textile material impregnated with a suitable preserving compound preferably such as asphalt ooded burlap wrapped around the cable and covered with a' layer of paper 26 spirally applied over the textile material. The textile material may be impregnated either before or after being applied to the cable and the preserving compound may be asphalt or other suitable compound capable of resisting chemical decomposition and also serving as a mechanical reenforcement for the cable.

-In some cases it may be advantageous to employ a cable constructed as shown in Figs. 2 and 5 having two or more layers i5 and I6 of metallic sheath applied over the paper wrapping prior to the application of the continuous tape or skelp which forms the water-tight tube 20. The additional layer or layers It are preferably composed of material similar to that of the metallic tape I5. The layer of metallic tape I8 may have the same direction of "lay as the layer I5 or the opposite direction as shown in Fig. 2 and the edges may overlap as shown in.FIg. 2 or the tape I8 may be applied in a manner similar to that described below in connection with Fig. 3.

In an alternate method of constructing the cable as shown in Figs. 3 and 6 the layer or layers of flexible sheath between the paper Il and the water-tight sheath may be formed and applied to provide an intermittent support for the sheath 2l and may take the forr'n of a tape or wire i1, somewhat thicker than the water-tight sheath 2l, or deformed by embossing or corrugating and applied over the paper wrapping I3 in a manner such that there is an intervening space between the edges of the tape or wire Il, or between the ridges of the bosses or corrugations.

The above described methods of forming an electric cable provide a flexible cable which when flexed will cause the sheath 20 to crinkle uniformly and the finished cable can withstand many ilexures and may be exed to a greater degree without the tendency of the water-tight sheath 20 to rip or crack.

It is to be understood that the invention is not to be limited to the particular embodiments shown, nor to the particular arrangements that have been described and shown in detail, but only by the scope of the appended claims.

What is claimed is:

l. In an electric cable having. an inner insulated conductor portion, a covering of paper rib-` bon applied spiraliy around the conductor portion, a metallic ribbon applied spiraliy around the paper ribbon. a thin metallic sheath applied over said metallic ribbon formed from sheet metal and having its edges joined to form a water-proof casf ing, a sheath of asphalt flooded burlap over said metallic sheath and a covering of paper ribbon applied over said asphalt flooded burlap.

2. In an electric cable having an inner insulated conductor portion, a covering of paper ribbon applied around the conductor portion, a metallic ribbon applied spiraliy around the paper ribbon and having its edges overlapped, a metallic waterproof sheath applied over said metallic ribbon,I a wrapping of textile material impregnated with preserving material over said metallic sheath, and a covering of paper applied over said impregnated textile material, said metallic waterproof sheath comprising a comparatively thin sheet of a metal selected from the class which consists of copper and brass and zinc, the edges `of which are joined together in a seam extending longitudinally of the cable.

3. In an electric cable having an inner insulated conductor portion, a covering of paper applied around the conductor portion, a relatively thick metallic ribbon applied spiraliy around the paper covering, a relatively thin metallic waterproof sheath applied over said metallic ribbon, a wrapping of textile material impregnated with preserving material over said metallic sheath,

and al covering of paper applied over said impregnated textile material, said metallic waterproof sheath comprising a comparatively thin sheet of a metal selected from the class'which consists of copper and brass and zinc, the edges of which are joined together in a seam extending longitudinally of the cable.

4. In an electric cable having an inner insuf lated conductor portion, a covering of paper ribbon applied around the conductor portion, a plurality of layers of metallic ribbon applied spiraliy around the paper ribbon, a metallic waterproof sheath applied over said metallic ribbon, a sheath of asphalt flooded burlap over said metallic sheath, and a covering of paper applied over said asphalt flooded burlap.

5. In an electric cable having an inner insulated conductor portion, a covering of paper ribbon applied around the conductor portion,a plurality of layers of metallic ribbon applied spirally around the paper ribbon the alternate layers of metallic ribbon having opposite directions of lay, a metallic waterproof sheath applied over said metallic ribbon, a sheath of preservative flooded textile over said metallic sheath, and a covering ofpaper ribbon applied over said preservative ilooded textile, said metallic waterproof sheath comprising a comparatively thin sheet of a metal selected from the class which consists of copper and brass and zinc, the edges of which are joined together in a seam extending longitudinally of the cable.

6. In an electric cable having an inner insulated conductor portion, a covering of paper ribbon applied around the conductor portion, a relatively thick metallic ribbon applied spiraliy around the paper ribbon with an intervening space between the edges of the metallic ribbon, a relatively thin metallic waterproof sheath applied over said metallic ribbon, a sheath of asphalt flooded burlap over said metallic sheath, and a covering of paper ribbon applied over said asphalt rlooded burlap.

7. In an electric cable having an innerinsulated conductor portion, a covering of paper ribbon applied spiraliy around the conductor portion, a metallic tape applied spiraliy around the paper ribbon with an intervening space between the adjacent outermost portions of the tape, a metallic waterproof sheath applied over said metallic ribbon, a sheath of asphalt hooded burlap over said metallic sheathand a covering of paper ribbon applied over said asphalt iiooded burlap.

8. In an electric cable having an inner insulated conductor portion, a covering of paper applied around the conductor portion, a metallic ribbon applied spiraliy around the paper covering, a relatively thin metallic waterproof sheath applied over said metallic ribbon, a wrapping of textile material impregnated with preserving maw terial over said metallic sheath, and a covering of paper applied over said impregnated textile material, said metallic water-proof sheath oomprising a comparatively thin sheet of metal selected from the class which consists of copper 5 and brass and zinc, the edges of which are joined together and the seam resulting from the edge joining operation extending longitudinally of the cable.

. ROY 1". LAYTON. 

